Various types of security systems usable to authenticate documents or other objects are known. For example, U.S. Pat. No. 4,906,988 to Copella entitled "Object Verification System and Method", assigned to the assignee of the present invention and incorporated herein by reference, discloses a particular form of a security system which utilizes characteristics of spaced-apart magnetic regions. Previously issued U.S. Pat. No. 4,837,426 to Pease et al. entitled "Object Verification Apparatus and Method" describes a particular form of a magnetic security system which is usable with a continuously extending magnetic region.
Other systems are known which utilize a randomly varying translucency characteristic of paper and the like. Security systems are also possible where another randomly varying characteristic, such as print variations, of an object or a document are available for use.
Prior systems have often utilized the randomly varying characteristics as they existed in the document or the object. While such systems are useful, there are times when it would be desirable to physically enhance or exaggerate the random variation at the time when the randomly varying characteristic is created.
The above noted Pease et al. patent makes reference to enhancing random magnetic regions by underprinting or overprinting with magnetic ink in the vicinity of the magnetic security region. The same patent also refers to embossing, scratching or other methods of removable of a portion of the magnetic material to create a more readily detectable characteristic.
Beyond creating an exaggerated or an enhanced security region by physically altering a portion of the region, it would be desirable to be able to do so in such a way so as to make duplication or copying of the enhanced regions difficult or impossible. Further, it would be desirable to be able to create an enhanced structure using a method which does not appreciably add to the cost of producing what might otherwise be a very inexpensive document.